To understand if vitamin D concentrations affect fertility, Pagliardini and colleagues measured 25(OH)D3 concentrations in 1,072 women visiting an infertility center. Overall, 40% of the women visiting the clinic were vitamin D insufficient (< 20ng/mL, 50 nmol/L) for the entire year. Being in the lowest quintile for 25(OH)D3 concentrations increased the risk of endometriosis. The prevalence of low vitamin D concentrations was lowest in the latter trimester of pregnancy. In other words, women with the lowest vitamin D concentrations were the least likely to reach full-term.

As discussed previously, vitamin D concentrations were inversely associated with adiposity (measured as body mass index, BMI). Fewer than 5% of the women were obese and there were numerous factors contributing to infertility – including male infertility.

Vitamins are not only essential for metabolism, conception requires viable sperm and eggs and then to support the growth and development of a fertilized egg to a healthy baby. For those wanting to have children, these studies show the importance of having 25(OH)D3 concentrations assayed for a healthy pregnancy and infant language development.